Process of extracting precious metals



Feb. 27, 1923.

WITNESSES;

c. c. MCBRIDE PROCESS OF EXTRACTING PRECIOUS METALS Filed Apr.

III/II III/III! II/I INVENTOR ATTO RN EY Patented Feb. 27, 1923.

CHARLES C. MGBRIDE, OF SANGER, CALIFORNIA.

PROCESS OF EXTRACTING PRECIOUS METALS.

Application filed April 23, 1921. Serial No. 463,995.

T 0 all whom it may concern:

Be it known that I, CHARLES C. MCBRIDE, a citizen of the United States,residing at Sanger, in the county of Fresno and State of California,have invented certain new and useful Improvements in Processes ofExtracting Precious Metals, of which the following is a specification.

The present invention relates to the recovery of precious metals, suchas gold, platinum and silver, from ores containing the same, and theprocess has been shown to give excellent results in the treatment of seasands containing such precious metals, such sea sands being found nativein a number of places. a i

The process consists essentially in agitating the said sands, or otherores carrying the said metals, preferably after crushing to about thesize of ordinary sea: sand, while the said ore sands are suspended in asolution of sodium chloride, preferably of about one to three per cent)strength, while passing a current of electricity from an insoluble anodein said liquor to an amalgamated lead plate in said liquor. For ordinarypurposes plain sea water is an excellent material to use as anelectrolyte and the agitation can easily be efi'ected by passing the oreor sand from one end to the other of a rotary cylinder having anamalgamated lead lining, suitably projecting ribs being provided foradvancing the ore or sand from one end of said. cylinder to the other.

The accompanying drawing represents the vertical section of an approvedform of apparatus for carrying out the process. In said drawing 10represents a tank made out of any suitable material not readily actedupon by the materials used in the process. Extending lengthwise of thistank is a drum 11, made of lead, the interior of which is coated withmercury. Instead of making the cylinder of lead it may be made of woodor like material having a lead lining. '12 represents a helical ridge orvein, which causes the ore to progress through the cylinder when thiscylinder is rotated for example by the pulley 13. At 14 is shown ahopper through which the sand or crushed ore is dropped into thereceptacle. The cylinder being rotated in the direction of the arrow 15,the ore will be picked up by the projecting end of the cylinder and fedin the direction of the arrow.

Located at any suitable point in the receptacle l0 belowthe normalliquor level therein (for example 16) is an insoluble anode 17. Thecurrent lead 18 is connected to the negative end of the electric circuitthis in turn being connected at 19 to .the lead cylinder.

Located at the outlet end of the cylinder is a sump 20 into which thetailings are dumped from which they are removed by an inclined screwconveyor 21, or otherwise.

. It isl-adviswble to feed the ore through 14 at such a rate as tomaintain a quantity of ore as shown at 22 in the inlet end of theelectrolytic vat.

As the cylinder revolves a portion of the pulp or sand is picked up andcarried through the cylinder and deposited in the sump 20 from which itis removed to waste. In this manner the ore material is brought intocontact with the amalgamated lead lining of the cylinder; The cylinderis so partitioned that a narrow path is made conforming to thecircumference of the cylinder and travelling spirally from the intakeend to the discharge end. During the passage of the pulp or sand throughthe cylinder it comes into repeated contact with the amalgamated leadlining of the cyl-v inder and the current of electricity passing fromthe insoluble anode tothe lead lining causes the gold, silver orplatinum (or mixtures of these) to be carried to and deposited upon theamalgamated lead plate. The electrolytic action is assisted by bothgravity and centrifugal force, whereby the removal of the preciousmetals from the ore is extremely rapid and complete. In addition to theabove mentioned physical advantages, more or less metallic sodium isdeposited upon the mercury, forming a sodium amalgam which assists inthe removal of the precious metal from the ores. Also the lowconductivity of the metallic lead increasesthe capillarity of the"mercury by contact.

In regard to the amalgamated lead plate, lead is selected particularlybecause lead is slightly less resistant electrically and is morepositive in the electromotive series than is mercury, this increasingthe clarity of the mercury by contact.

For supporting the cylinder suitable brackets as shown at 25 may beprovided, these being carried by shafts 26 passing through stufiingboxes 27 and through suit ablejom'nal beaes 28.

ramneo In addition to the helical flange 12, the cylinder may have aspiral construction as indicated at the left hand end of the figure, theportion of the cylinder 29 being lapped inside of theuportion 30. Thisgives muchmore of a tumbling action to the ore in pass ing through thecylinder or conveyor.

I claim: A process of extracting precious metal from ore, whichcomprises continuously agitating a non-progressing solution containingessentially an alkali metal chloride while.

agitating and tumbling an ore of a sand-like consistency in saidsolution, and While causing said ore to progress from one end of thesolution to the other, While passing an electrolytic current throughsaid mixture,

J from an insoluble anode to an amalgamated lead cathode.

In testimony whereof I afix my signature. 20

CHARLES C. MCBRIDE.

